This application claims priority from Italian Utility Model Application No. MI99U000449, filed Jul. 13, 1999 and hereby incorporated by reference.
The present invention relates to an automatic cleaning device for a vehicle traffic detecting device, which provides for ensuring long-term, maintenance-free efficiency of the detecting device, even in heavy traffic conditions in which the performance and efficiency of the detecting device are rapidly impaired by severe pollutant emissions and atmospheric agents. The invention also extends to an integrated assembly comprising a vehicle traffic detecting device and an automatic cleaning device therefor.
As is known, vehicle trafficxe2x80x94for example, at a tollway tollboothxe2x80x94is detected by means of detecting devices, e.g. optical, normally defined by a light beam emitter and a corresponding receiver. When the beam is cut off by a vehicle passing between the emitter and receiver, the device detects the passage of a vehicle. A number of pairs of emitters/receivers can be used to also determine the type (in particular, size) and speed, etc. of the vehicle. The beam generating and receiving components of the emitter and receiver are normally housed in corresponding casings and protected by corresponding transparent surfaces through which the beam travels. As should be appreciated, for detecting devices of this sort to function correctly, the transparency of the surfaces protecting the internal components must be maintained. A major drawback of detecting devices of this sort, however, is rapid fouling, particularly of the transparent surfaces, by pollutant substances contained in vehicle exhaust gas, and by atmospheric agents such as dust, rain, and the like. The problem is further compounded in the case of devices used at tollway tollbooths and the like for not only detecting traffic but also for opening/closing pay toll barriers. In which case, being located in a high exhaust gas density area, the device is subject to rapid fouling and, to work properly, must be cleaned frequently, which, at present, is done by hand by an operator at relatively high cost.
It is an object of the present invention to provide an automatic cleaning device for a vehicle traffic detecting device, designed to provide a straightforward, low-cost solution to the above problem.
According to the present invention, there is provided an automatic cleaning device for a vehicle traffic detecting device, characterized by comprising at least one cleaning unit, in turn comprising: fastening means for assembly to a casing of said detecting device; dispensing means for dispensing a transparent film; actuating means for feeding said film along a predetermined path and positioning said film in front of said detecting device; and control means for automatically activating said actuating means in response to a predetermined signal from said detecting device.
The invention also relates to an integrated assembly comprising a vehicle traffic detecting device and an automatic cleaning device; said detecting device comprising an emitter and a receiver for respectively emitting and receiving a beam of electromagnetic radiation, and which are located facing each other at respective opposite ends of a path of said beam; the integrated assembly being characterized by comprising a cleaning device, in turn comprising a first and a second cleaning unit for respectively cleaning said emitter and said receiver, and control means for automatically activating said cleaning units; said cleaning units comprising respective dispensing means for dispensing respective transparent films, and respective actuating means for feeding said films along respective predetermined paths and positioning said films respectively in front of said emitter and said receiver; said control means activating said actuating means of both said cleaning units in response to a predetermined variation in said beam.
The cleaning device according to the invention therefore provides for ensuring long-term efficiency of the detecting device, while at the same being extremely cheap and easy to produce and assemble, and cheap to run. Featuring a roll-up film, the cleaning device, in fact, provides for guaranteed efficiency of the detecting device at all times. That is, according to the invention, it is the transparent films protecting the detecting device components (in particular, closing the openings of the emitter and receiver of the detecting device) which are directly exposed to external pollutants. When the portion of film over the emitter or receiver becomes so dirty as to fail to ensure correct operation of the detecting device, the actuating means of both the emitter and receiver cleaning units are activated to feed the films of both cleaning units forward and position respective clean portions of film in the work position in front of the respective openings of the emitter and receiver. The film feed actuating means may advantageously be activated in response to a prolonged interruptionxe2x80x94over and above a predetermined minimum period of timexe2x80x94of the beam between the emitter and receiver.
When the reel of film each cleaning unit is provided with runs out, the cleaning units can be opened to change the drums alone, or the cleaning units as a whole may be changed. This is particularly easy, especially when, as in a preferred embodiment of the invention, the cleaning units are of modular design. In which case, the cleaning units can also be fitted easily, with only minor alterations, to existing detecting devices. According to the invention, in fact, the roll-up-film cleaning units may either be produced separately and fitted to existing detecting devices, or be integrated in the detecting devices themselves.